These are really exciting news, during MMS 2011 it was announced from the Configuration Manager Team, that there is a tool available in Community Technology Preview (CTP )Version which will facilitate the migration of Remote Site Servers that need to be retained during the Side-by-Side Migration process of Configuration Manager 2007 to Configuration Manager 2012.

Here is the official info, the link at the connect site to download it can be found at the end of the post:

The Configuration Manager P2V Migration Toolkit was designed to assist in situations where there are remote Configuration Manager 2007 site servers that need to be retained during the side-by-side migration process to Configuration Manager 2012.